Вычислите sin t и cos t, если: а) t = 5 пи / 6 б) t = 5 пи/4 в) t = 7 пи/6 г) t = 9 пи/4

Используя формулы приведения и учитывая периодичность тригонометрических функций, получим:

а) sin (5π/6) = sin (π - π/6) = sin (π/6) = 1/2;

cos (5π/6) = cos (π - π/6) = - cos (π/6) = - √3/2.

б) sin (5π/4) = sin (π + π/4) = - sin (π/4) = - √2/2;

cos (5π/4) = cos (π + π/4) = - cos (π/4) = - √2/2.

в) sin (7π/6) = sin (π + π/6) = - sin (π/6) = - 1/2;

cos (7π/6) = cos (π + π/6) = - cos (π/6) = - √3/2.

г) sin (9π/4) = sin (2π + π/4) = sin (π/4) = √2/2;

cos (9π/4) = cos (2π + π/4) = cos (π/4) = √2/2.